The i.MX27/31 have the second chip select enabled by reset default.
This can be considered as a hardware bug, because even boards which
need this settings cannot work out of reset because of the missing
initialization sequence. Detect this reset default setting and disable
this chipselect then to be able to properly detect the SDRAM size.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>